With the increasing speed of PCB faailo fesuiaʻi, aso nei PCB tagata mamanu manaʻomia le malamalama ma faʻatonutonu le faʻalavelave o PCB faʻamau. Faʻatatau i taimi pupuu faʻailo taimi faʻasalalau ma maualuga uati fua o aso nei faʻanumeraina matagaluega, PCB faʻailoga e le toe faigofie faʻafesoʻotaʻiga, ae laina faʻasalalau.

Faʻafefea ona pulea PCB impedance

I le faʻataʻitaʻiga, e manaʻomia le taofiofia o faʻalavelave faʻafuaseʻi pe a o le numera televave faʻavaomalo e sili atu i le 1ns poʻo le analog analog ua sili atu i le 300Mhz. O se tasi o tapulaʻa taua o le PCB trace o lona uiga faʻafitauli (o le fua faʻatatau o le voltage i le taimi nei a o le galu femalagaaʻi i luga o le faʻailo laina laina). The characteristic impedance of wire on printed circuit board is an important index of circuit board design, especially in PCB design of high frequency circuit, it must be considered whether the characteristic impedance of wire is consistent with the characteristic impedance required by device or signal. This involves two concepts: impedance control and impedance matching. This paper focuses on impedance control and lamination design.

Faʻatonutonu

Faʻatonutonuina EImpedance, o le conductor i le matagaluega laupapa o le ai ai ituaiga uma o faʻailo faʻailo, ina ia mafai ai ona faʻaleleia le lafoina fua ma e tatau ona faʻateleina lona taimi, pe a fai o le laina lava ia ona o le faʻapipiʻiina, faʻapipiʻiina mafiafia, uaea lautele ma isi eseese itu, o le a mafua ai impedance suiga suiga, le faʻailoga faʻaletonu. O le mea lea, o le impedance aoga o le conductor luga o le maualuga-saosaoa laupapa matagaluega e tatau ona faʻatonutonuina i totonu o se faʻapitoa, lauiloa o le “impedance control”.

The impedance of a PCB trace will be determined by its inductive and capacitive inductance, resistance, and conductivity coefficient. O le autu mafuaʻaga aafia ai le impedance o PCB wiring o: le lautele o le uaea apamemea, le mafiafia o le uaea apamemea, o le dielectric tumau o auala, le mafiafia o auala, le mafiafia o pad, le ala o le eleele uaea, o uaea faataamilo i uaea , ma isi PCB impedance mai le 25 i le 120 ohm.

I le faʻataʻitaʻiga, o le laina faʻasalalau PCB masani lava ona aofia ai se faʻailoga, tasi pe sili atu faʻasino vaega, ma mea faʻaʻeseʻese. Lolomi ma faʻavae fausia le faʻatonutonu impedance. PCBS o le a masani ona tele-faʻaputuga, ma o le faʻatonutonu impedance mafai ona fausiaina i ni auala eseese. However, whatever method is used, the impedance value will be determined by its physical structure and the electrical properties of the insulating material:

Lautele ma mafiafia o faailoga faailo

The height of the core or prefill material on either side of the trace

Fetuʻunaiga o faʻailoga ma le ipu mafolafola

Insulation constants of core and prefilled materials

O laina faʻasalalau PCB e oʻo mai i ni itu autu se lua: Mikerostrip ma Stripline.

Microstrip:

O le microstrip laina o se fasi ave taʻavale ma se vaalele faʻasino i luga o le na o le tasi le itu, ma le pito i luga ma autafa faʻaalia i le ea (po o coated), luga o le laualuga o le faʻamama faifai pea Er matagaluega laupapa, ma le sapalai o le eletise poʻo le faʻavaeina o se faʻasino. E pei ona faʻaalia i lalo:

Faʻaaliga: I le gaosiga o le PCB, e masani ona faʻaʻofu e le tagata gaosi laupapa le pito i luga o le PCB ma le isi vaega o le suauʻu lanumeamata.

Laina valivali:

O le lipine laina o se lipine o uaea tuʻu i le va o vaʻalele e lua, e pei ona faʻaalia i le ata o loʻo i lalo. O le dielectric Constants o le dielectric sui e H1 ma H2 mafai ona eseese.

The above two examples are only a typical demonstration of microstrip lines and ribbon lines. There are many kinds of specific microstrip lines and ribbon lines, such as coated microstrip lines, which are related to the specific laminated structure of PCB.

The equations used to calculate the characteristic impedances require complex mathematical calculations, usually using field solving methods, including boundary element analysis, so using the specialized impedance calculation software SI9000, all we need to do is control the parameters of the characteristic impedances:

Dielectric tumau Er, laina lautele W1, W2 (trapezoid), uila mafiafia T ma faʻapipiʻi vaega mafiafia H.

W1, W2:

The calculated value must be within the red box. Ma faapena lava.

SI9000 o loʻo faʻaaogaina e fuafua ai pe o le impedance control manaoga ua faʻamalieina:

Muamua fuafua le tasi-iuga impedance pulea o DDR faʻamaumauga laina:

LUGA vaega: 0.5oz ‘apamemea mafiafia, 5MIL uaea lautele, 3.8mil mamao mai le vaalele faʻasino, dielectric tumau 4.2. Filifili le faʻataʻitaʻiga, sui i le faʻatapulaʻaina, ma filifili Lossless Calculation, e pei ona faʻaalia i le ata:

CoaTIng o lona uiga coaTIng, ma afai e leai se coaTIng, faʻatumu le 0 i le mafiafia ma le 1 i dielectric (dielectric tumau) (ea).

Substrate tu mo substrate vaega, o lona uiga, dielectric vaega, masani faʻaaogaina fr-4, mafiafia fuafuaina e impedance fuafua polokalama, dielectric tumau 4.2 (taimi laititi ifo i le 1GHz).

Click on Weight (oz) to set the thickness of the copper layer, which determines the thickness of the cable.

9. Prepreg / Core manatu o le faʻaʻesega vaega:

PP (Prepreg) o se ituaiga o dielectric mea, aofia ai o tioata alava ma epoxy resin. Core o le TYPE moni o le PP auala, ae o ona itu e lua o loʻo ufiufi i apamemea foil, ae o le PP e leai. A o faia multilayer laupapa, autu ma PP e masani ona faʻaaoga faʻatasi, ma PP e faʻaaogaina e fusia i le va o le autu ma le autu.

10. Mataupu e manaʻomia le faʻalogo i le PCB lamination design

(1) Faʻafitauli tau i le taua

O le vaega mamanu o PCB tatau ona symmetrical, o lona uiga, o le mafiafia o feololo vaega ma apamemea vaega o vaega taitasi tatau ona symmetrical. Ave le ono faaputuga mo se faʻataʻitaʻiga, o le mafiafia o le pito i luga-GND ma le pito i lalo-paoa auala e tatau ona ogatasi ma le mafiafia o le ‘apamemea, MA o le GND-L2 ma le L3-POWER auala e tatau ona ogatusa ma le mafiafia o apamemea. Lenei o le a le faʻaletonu pe a laminating.

(2) O le faʻailo vaega e tatau ona vavalalata faʻatasi ma le vaalele fesoʻotaʻi felataʻi (o lona uiga, o le mafiafia va i le va o le faʻailoga vaega ma le tuaoi apamemea -O le vaega e tatau ona matua laʻititi); O le faʻaaogaina o le paʻu o le paʻu ma le faʻalanuina o le ‘apa memea e tatau ona soʻosoʻo faʻatasi.

(3) I le tulaga o le saoasaoa tele, o isi vaega e mafai ona faʻaopopoina e vavaeʻese ai le vaega o faʻailo, ae fautuaina e aua le tuʻufaʻatasia le tele o eletise eletise, lea e ono mafua ai le faʻalavelave a le pisapisao.

(4) O le tufatufaina o masani laminated mamanu faʻavae o loʻo faʻaalia i le laulau lea:

(5) Lautele mataupu faʻavae o le faʻavasegaina vaega:

Lalo o le vaega luga (o le lona lua vaega) o le eleele vaʻalele, lea e maua ai le masini puipuia vaega ma le vaʻalele vaʻaia mo le pito i luga vaega faʻamau;

O laina faʻailo uma e sosoʻo ma le vaʻalele eleele i le mamao e mafai ai.

Aloʻese mai tuʻusaʻo tuʻusaʻo i le va o ni faʻailo se lua i le mamao e mafai ai;

O le eletise autu sapalai e tatau ona latalata atu pe a mafai;

Symmetry o laminate fausaga e amanaʻia.

For the layer layout of the motherboard, it is difficult for the existing motherboard to control the parallel long-distance wiring, and the working frequency of the board level is above 50MHZ

(Mo tuutuuga i lalo ole 50MHZ, faʻamolemole tagaʻi i ai ma malolo talafeagai), o le faʻavae mataupu faʻavae ua fautuaina:

Luga vaega ma maopoopo luga o vaʻaiga atoa vaʻalele (talita);

Leai sosoʻo faʻatasi fesoʻotaʻiga vaega;

O laina faʻailo uma e sosoʻo ma le vaʻalele eleele i le mamao e mafai ai.

O le ki faailo e tuaoi ma le faʻavaeina ma e le sopoia le vaevaega vaega.